Cable and satellite television transmission systems have become increasingly robust in recent years, moving beyond the more traditional television and pay-per-view (PPV) services that prevailed in the 1990's. Accordingly, consumer devices, such as cable set top terminals have become increasingly more versatile to accommodate new system capabilities. For example, the DCT-2000 (digital consumer terminal) set top box by Motorola, Inc. of Horsham, Pa. can be configured to support real time reverse path communications, providing a gateway to interactive services such as video on demand (VOD), Internet Access, Email, Home Shopping, E-commerce and the like.
To support these different applications and services, the set top box has a plurality of Processor Identifier (PID) processors. PIDs carry data to identify data streams within an MPEG multiplex. A PID Processor is a device within the television set top converter box that knows how to “listen” for a specific PID for which it has been requested to “listen”, and separates out data streams (PIDs) from the overall MPEG multiplex stream received by the set top box. Each PID processor can be programmed to respond to a respectively different stream input. For example, the DCT-2000 has a hardware limit of six PID packet processors. There may be many more data streams on the cable, but at any given time, the DCT-2000 can only process up to six unique MPEG (motion picture exploitation group) streams.
However, due to the design of the “cable system” (which includes the digital data stream design and set top management design), many of these PID processors are typically allocated to core system functions, which are used for television viewing. The core system functions include such basics as telling the set top how to find other channels and other data, telling the set top for which channels/data it is authorized, sending new control software to the set top, verifying that the set top is working correctly, sending configuration information as to the set top network connection, and the like.
With the advent of additional television services, additional application programs are required by the set top box. Data links are needed to support third party applications running within the set top box. For example, the WorldGate service (by WorldGate Inc. of Trevose, Pa.) needs a data link to exchange data to control when to display an “Interactive Content Here” button, and uses a link to send down the “TV Menu Pad” images. Television programming applications guide may need a link to download the TV schedule. The system uses the links to get the time and to download new software. The number of PID processors is limited. In many systems, no more PID processors are available to process the incoming data streams needed by these applications. In this situation, no new programs or features can be added that require dedicated PIDs, because there are no more PID processors available to handle the data. For example, in some systems, most of the available PIDs were allocated for system management and thus in some cases leaving none available for a middleware layer to do its work.
A method and system are desired to allow the addition of new set top application programs that communicate with the headend, without requiring replacement of existing set top boxes.